Lens, LED Module and Illumination System having Same

ABSTRACT

An illumination system includes at least an LED module, and at least an illuminated area. The LED module includes an LED, and a lens mounted in light path of the LED. The lens includes a light source recess, a first light emitting surface, a critical reflecting surface, and a second light emitting surface intersecting with the first light emitting surface and being on same side with the first light emitting surface. The first light emitting surface can receive more light quantity than the second light emitting surface. Although the light emitted from the first light emitting surface may have greater attenuation than the light emitted from the second light emitting surface, light emitted from the first light emitting surface can make up the intensity losses of attenuation as the first light emitting surface receives more light quantity than the second light emitting surface. As a result, the illumination system  100  have uniform illumination pattern.

RELATED APPLICATION

This application claims benefit of priority to Chinese ApplicationCN201210359368.8, filed on Sep. 13, 2012 with the State IntellectualProperty Office of the People's Republic of China.

BACKGROUND

1. Technical Field

The disclosure relates to electrical lighting devices, and moreparticularly to an illumination system providing an uniform illuminationpattern, lens and LED module used in the illumination system.

2. Description of the Related Art

For years, people have used traditional incandescent or fluorescencelighting apparatus in order to address their interior lighting concerns.However, such lighting apparatus presents a number of drawbacks. Forexample, the popular halogen apparatus presents the following drawbacks,such as relatively high power consumption, inefficiency of lightdispersion due to the placement of its metal shield in the line sight ofthe halogen bulb, and its limited effectiveness in preventing glare fromthe halogen bulb.

Recently, a number of LED lighting apparatuses have been designed toreplace the halogen apparatus, as well as other traditional incandescentor fluorescence lighting apparatuses. But, due to mediocre light output,LED used in the past was primarily limited to applications where onlysmall surface areas were illuminated. In these applications the lightwas concentrated into a narrow beam using an optic designed to take thewide angle light output of an LED and collimate it using a lens,discussed below with respect to FIG. 11. FIG. 11 shows a traditionallight illumination system. The light illumination system includes anilluminated area 1, and a LED light module 2 positioned beside theilluminated area 1. The LED light module 2 has a light emitting surface3 and light 4 emitted forward of the light emitting surface 3 illuminatethe illuminated area 1. Understandably, regardless of where the LEDlight module 2 is disposed with relationship of the illuminated area 1,part of the light 4 illuminate the illuminated area 1 which is closer tothe LED light module 2 and the other illuminate the illuminated area 1which is farther to the LED light module 2. Since the performance of theabove illumination is inevitable, part of the light 4, which illuminatethe illuminate area 1 and is farther to the LED light module 2, has moreattenuation than the other which illuminate the illuminate area 1 and iscloser to the LED light module 2. However, the light 4 emitted from thelight emitting surface 3 has same initial light intensity. As a result,the illumination values of the illuminated area 2 vary with the distancebetween the illumination area 1 and the LED light module 2. Examples ofsome applications of the light illumination system include exhibitionhall, showcase, and so on. These new applications require differentoptical designs. In particular these applications require uniformillumination in the illumination area 2 for improving the sense ofquality of the showed products to people.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the embodiments can be better understood with referencesto the following drawings. The components in the drawings are notnecessarily drawn to scale, the emphasis instead being placed uponclearly illustrating the principles of the embodiments. Moreover, in thedrawings, like reference numerals designate corresponding partsthroughout two views.

FIG. 1 is a light path view of an illumination system in accordance witha first embodiment of the disclosure.

FIG. 2 is an isometric view of one lens of the illumination system ofFIG. 1.

FIG. 3A and FIG. 3B are section views of a LED module having the lens ofFIG. 2 taken along B-B line and an LED located at different positions.

FIG. 4A-FIG. 4D are section views of the lens of the illumination systemof FIG. 1 having different light emitting surface.

FIG. 5 is a plan view of the lens of FIG. 2.

FIG. 6A and FIG. 6B are partially enlarged views of the lens of FIG. 3Aat B and the lens of FIG. 5 at C.

FIG. 7 is a light path view of the illumination system of FIG. 1 havingthe lens of FIG. 4A.

FIG. 8 is a light path view of the illumination system of FIG. 1 havingthe lens of FIG. 4B.

FIG. 9 is an isometric view of a lens in accordance with secondembodiment of the disclosure.

FIG. 10A-FIG. 10C are plan views of the lens of FIG. 9 which havedifferent curvature relate to an optical axis thereof.

FIG. 11 is a light path view of a traditional illumination system inprior art.

DETAILED DESCRIPTION

The disclosure is illustrated by way of example and not by way oflimitation in the figures of the accompanying drawings. It should benoted that references to “an” or “one” embodiment in this disclosure arenot necessarily to the same embodiment, and such references mean atleast one.

Referring to FIG. 1, a light path view of an illumination system 100according to a first embodiment is shown. The illumination system 100includes at least a LED module 10, and at least an illuminated area 20according to each of the LED module 10. In actual applications, theremay have many LED modules 10 which are determined by the quantity andthe area of the illumination area 20. In the present embodiment, onlyfor explaining the present disclosure, one LED module 10 and oneilluminated area 20 are shown as example. Understandably, theillumination system 100 includes other components, such as house, basefor mounting the LED module 10, cover, and power source for providingpower to the LED module 10, and so on, but they need not be explained asthey are well known by persons in the art.

The LED module 10 includes a LED 12, and a lens 11 arranged on lightpath of the LED 12. Referring to FIG. 2 and FIG. 3, the lens 11 includesan optical axis 111, a light source recess 112 for receiving a lightsource, a first light emitting surface 113 facing to the light sourcerecess 112, a second light emitting surface 114 intersecting with thefirst light emitting surface 113 and being on same side of the lightsource recess 112 with the first light emitting surface 113, a criticalreflection surface 115 formed between the light source recess 112 andthe first, second light emitting surfaces 113, 114, and a transitionalsurface 116 formed between the critical reflecting surface 115 and thefirst, second light emitting surface 113,114.

The optical axis 111 is a universal feature for all of lens and used todispose the light source, namely the LED 12. Moreover, the optical axis111 is a guide for optic design.

The light source recess 112 is used for mounting the light source, suchas the LED 12, or other traditional light source. In the presentembodiment, the light source is the LED 12. When dimension scale betweenthe lens 11 and the light source is same as that between the lens 11 andthe LED 12, the light source may be other traditional light source, suchas incandescent or fluorescence lighting apparatuses, and so on. Asshown in FIG. 3A and FIG. 3B, the LED 12 may be mounted into the lightsource recess 112 or at outer side of the light source recess 112. Whenthe LED 12 is disposed into the light source recess 112, a bottom sideof the LED 12 is flush with an end of the light source recess 112 forsufficiently taking advantage of the light emitted forward of the LED 12and ease to assemble the lens 11 and the LED 12. When the LED 12 ismounted at outer side of the light source recess 112, a light emittingside of the LED 12 is flush with the end of the light source recess 112for sufficiently taking advantage of the light emitted forward of theLED 12. In the present embodiment, the bottom side of the LED 12 isflush with the end of the light source recess 112. The light sourcerecess 112 has a central axis which overlaps with the optical axis 111of the lens 11 for ease to optic design.

The first light emitting surface 113 is configured for refracting thelight emitted forward of the LED 12 to illuminate a part of theilluminated area 20 which is father to the LED module 10 and has a planview or a cambered view. In order to control beam width of the lightemitted forward of the LED 12 so as to form controlled illuminationpattern on the illuminated area 20, a plurality of convex lenses 1131are formed in the radial direction and in the circumferential directionaround the LED 12 which is provided at the center thereof. As shown inFIG. 6A, it is a partially enlarged view of FIG. 3A at B, and shows aradius R and a height h of the convex lenses 1131. FIG. 6B, which is apartially enlarged view of FIG. 5 at C, shows as hexagonal shapedregions having a lateral dimensional L. The convex lenses 1131 have theradius R, the height h, and the lateral dimensional L which are designedaccording to beam wide of incident light. According to embodiment of thepresent invention, the convex lenses 1131 can be made to providedifferent beam widths by varying the parameters such as R, h, and L. Forexample, in one embodiment, a configuration with R=3.0 mm, h=0.1 mm,L=1.33 mm is used for a narrow beam having a beam width of about 12-17degrees; R=2.0 mm, h=0.55 mm, and L=3.0 mm is used for a wide beamhaving a beam width of about 25-30 degrees.

The second light emitting surface 114 is on same side of the lightsource recess 112 with the first light emitting surface 113, and anintersecting line 1141 is formed between the first light emittingsurface 113 and the second light emitting surface 114. Needed to furtherexplain, the intersecting line 1141 may not be presented on the lens 11in actual manufacture and is replace by an arc having certain curvature,as shown FIG. 5A-FIG. 5B. The second light emitting surface 114 isconfigured for refracting the light emitted forward of the LED 12 toilluminate another part of the illuminated area 20 which is closer tothe LED module 10. As same as the first light emitting surface 113, aplurality of convex lenses are formed on the second light emittingsurface 114 and have same configuration and operating principle.Understandably, when the illuminated area 20 has a wide area, the convexlenses on the first, second light emitting surface 113, 114 may be notformed thereon. The intersecting line 1141 is spaced with the opticalaxis 111 so as to that light emitted from the second light emittingsurface 114 has different light intensity with that emitted from thefirst light emitting surface 113.

As shown in FIG. 3A and FIG. 3B, section views of the lens 11 arepresented. The section view is taken along the optical axis 111 andperpendicular to the intersecting line 1141. A profile of the sectionhas at least one tangent line thereon which has an acute angle with theoptical axis 111 along the emitting orientation of the light emittingfrom the first, second light emitting surfaces 113, 114. In result,according to the above rules, at least three samples can be deduced outas shown in FIG. 3A, and FIG. 4A-FIG. 4D. Referring to FIG. 3A, thefirst light emitting surface 113 has a plan view and has at least onetangent line which has an acute angle with the optical axis 111 alongthe light emitting orientation. The second light emitting surface 114has a cambered view and has a number of tangent lines which have acuteangle or obtuse angle with the optical axis 111. As shown in FIG.4A-FIG. 4D, at least one of the first, second light emitting surfaces113, 114 has at least one tangent line which has an acute angle with theoptical axis 111 along the light emitting orientation. In the presentembodiment, the first light emitting surface 113 has a plan view, andthe second light emitting surface 114 has a cambered view.

The critical reflection surface 115 is formed a inclined surface like amortar to reflecting the light emitted form the LED 12 into the firstlight emitting surface 113 and the second light emitting surface 114 andis designed to have an angle capable of reflecting the light emittedfrom the LED 12 onto the first light emitting surface 113 and the secondlight emitting surface 114.

The transitional surface 116 is formed between peripheries of the first,second light emitting surfaces 113, 114 and periphery of the criticalreflection surface 115. The transitional surface 116 neither receiveslight nor reflect or refract light, only is configured for forming thefirst, second light emitting surfaces 113, 114.

The LED 12 is a semiconductor light source and transforms power intolight. The LED 12 presents many advantages over traditional lightsources including lower energy consumption, longer lifetime, improvedphysical robustness, smaller size, and faster switching. A center of theLED 12 is arranged on the optical axis 111 of the lens 11 for ease tooptic design.

The illuminated area 20 is an object illuminated by the LED module 10and may be a plan or a curve. In the present embodiment, only forexplaining the configuration and principle of the disclosure, theilluminated area 20 is a plan and may be a picture exhibited in museumor selling goods placing in the freezer of supermarket, and so on. Asshown in FIG. 1, when assembling the LED module 10, light emitted fromthe first light emitting surface 113 illuminate the illuminated area 20which is farther to the LED module 10, while light emitted from thesecond light emitting surface 114 illuminate the illuminated area 20which is closer to the LED module 10.

In use, the light emitted from the first light emitting surface 113illuminate the illuminated area 20 which is farther to the LED module 10after refracted by the first light emitting surface 113. The lightemitted from the second light emitting surface 114 illuminate theilluminated area 20 which is closer to the LED module 10 after refractedby the second light emitting surface 114. Moreover, the intersectingline 1141 is spaced with the optical axis 111 and is located at side ofthe second light emitting surface 114 in the present embodiment, and theLED 12 is arranged in the optical axis 111, the first light emittingsurface 113 may receive more light quantity than the second lightemitting surface 114. In result, although the light emitted from thefirst light emitting surface 113 may have greater attenuation than thelight emitted from the second light emitting surface 114 as the lightemitted from the first light emitting surface 113 illuminate theilluminated area 20 which is farther to the LED module 10, light emittedfrom the first light emitting surface 113, which is father to theilluminated are, can make up the intensity losses of attenuation as thefirst light emitting surface 113 receives more light quantity than thesecond light emitting surface 114. As a result, the illumination patternwhich is closer to the LED module 10 has basically same luminance withthe illumination pattern which is father to the LED module 10. That isto say, the illumination system 100 has basically uniform illuminationpattern. In addition, the profile of section of the second lightemitting surface 114 has a number of tangent lines which have acuteangle and obtuse angle with the optical axis 111, therefore lightreceived by the second light emitting surface 114 is scattered, which iscontributed to reduce the light intensity of the light emitted from thesecond light emitting surface 114. Further, the light emitted from thefirst light emitting surface 113 may have more light quantity so as tomake up the intensity losses of the attenuation. Here, “basically” meansthat when illuminance values measured by an illuminance meter at twosides of the illumination area 20, which is father to and close to theLED module 10, are not absolutely equal. But it is difficult todistinguish for people to observe via naked eyes, therefore, theilluminated area 20 has a uniform illumination pattern for naked eyevision.

The light path of the illumination system 100 using the lens 11 of FIG.4A is shown in FIG. 7. With regard to the lens 11 of FIG. 4A, the first,second light emitting surfaces 113, 114 have plan views. Since theintersecting line 1141 is spaced with the optical axis 111 and islocated at side of the second light emitting surface 114, and the LED 12is arranged in the optical axis 111, the first light emitting surface113 may receive more light quantity than the second light emittingsurface 114. In result, although the light emitted from the first lightemitting surface 113 may have greater attenuation than the light emittedfrom the second light emitting surface 114 as the light emitted from thefirst light emitting surface 113 illuminate the illuminated area 20which is farther to the LED module 10, light emitted from the firstlight emitting surface 113 can make up the intensity losses ofattenuation as the first light emitting surface 113 receives more lightquantity than the second light emitting surface 114. As a result, theillumination pattern which is closer to the LED module 10 has basicallysame luminance with the illumination pattern which is father to the LEDmodule 10. That is to say, the illumination system 100 have basicallyuniform illumination pattern.

The light path of the illumination system 100 using the lens 11 of FIG.5B is shown in FIG. 7. With regard to the lens 11 of FIG. 4B, the first,second light emitting surfaces 113, 114 have cambered view. The lightemitted from the cambered view is scattered, and the intersecting line1141 is located at side of the second light emitting surface 114.Therefore, the first, second light emitting surface 113, 114 havedifferent light quantity. In result, the father side and close side ofthe illuminated area 20 related to the LED module 10 have basicallyuniform illumination pattern.

Referring to FIG. 9, a lens 21 according to a second embodiment isshown. The lens 21 includes an optical axis 211, a light source recess212 for receiving a light source, a first light emitting surface 213facing to the light source recess 212, a second light emitting surface214 intersecting with the first light emitting surface 213 and being onsame side of the light source recess 212 with the first light emittingsurface 213, a critical reflection surface 215 formed between the lightsource recess 212 and the first, second light emitting surfaces 213,214, a transitional surface 216 formed between the critical reflectingsurface 215 and the first, second light emitting surface 213, 214, and athird light emitting surface 217 formed between the light source recess212 and the second light emitting surface 216.

The optical axis 211, the light source recess 212, the first, secondlight emitting surface 214, and the critical reflection surface 215 havesame configuration and work principle with that of the lens 11 of thefirst embodiment. Therefore, the detailed description is omitted.

The third light emitting surface 217 extends from the light sourcerecess 212 to the second light emitting surface 214, and light emittedfrom the third emitting surface 217 illuminate the illuminated areawhich is closer to the LED module. According to optic distributiondesign, the third light emitting surface 217 may have a plan view or acambered view. Namely, the third light emitting surface 217 may have apositive curvature or a negative curvature related to the optical axis212. FIG. 10A, FIG. 10B, and FIG. 10C respectively show three style ofthe third light emitting surface 217. In the present embodiment, thethird light emitting surface 217 has a cambered view having a positivecurvature related to the optical axis 111. In the plan views of FIG.10A, FIG. 10B, and FIG. 10C, the third light emitting surface 217 has anintersecting line with the second light emitting surface 214 and atangent line of the intersecting line in peak is parallel to anintersecting line of the first, second light emitting surfaces 213, 214in order to insure maximum light quantity to illuminate the illuminatedarea. For changing light emitting orientation of the third lightemitting surface 217, a profile of section of the third light emittingsurface 217 along the optical axis 211 may be parallel to the opticalaxis 211 or have an inclined angle with the optical axis 211. Inaddition, the third light emitting surface 217 may be spaced with thelight source recess 212 or passed through the light source recess 212 soas to control the light quantity thereof. The third light emittingsurface 217 is configured for enlarging the illumination pattern of theilluminated area.

While the disclosure has been described by way of example and in termsof exemplary embodiment, it is to be understood that the disclosure isnot limited thereto. To the contrary, it is intended to cover variousmodifications and similar arrangements (as would be apparent to thoseskilled in the art). Therefore, the scope of the appended claims shouldbe accorded the broadest interpretation so as to encompass all suchmodifications and similar arrangements.

What is claimed is:
 1. A lens having an optical axis and a light sourcerecess for disposing a light source, the lens further comprising: afirst light emitting surface facing to the light source recess; and asecond light emitting surface intersecting with the first light emittingsurface and being on same side of the light source recess with the firstlight emitting surface, an intersecting line formed between the firstlight emitting surface and the second light emitting surface, and spacedwith the optical axis, a profile of section of the first, second lightemitting surface, which is taken along the optical axis andperpendicular to the intersecting line, having at least one tangent linewhich has an acute angle with the optical axis along the emittingorientation of the light emitted from the first, second light emittingsurface.
 2. The lens of claim 1, wherein the first light emittingsurface has a plan view or comprises at least a concave surface.
 3. Thelens of claim 1, wherein the second light emitting surface has a planview or a cambered view.
 4. The lens of claim 1, wherein the first lightemitting surface and the second light emitting surface have a pluralityof convex lenses disposed thereon, each of the convex lenses have aradius, a height and a lateral dimensional which are designed accordingto beam wide of incident light.
 5. The lens of claim 1, wherein the lensfurther comprises a critical reflecting surface formed between thefirst, second light emitting surface and the light source recess, atransitional surface is formed between the critical reflecting surfaceand the first, second light emitting surface.
 6. The lens of claim 1,wherein the light source recess has a central axis which overlaps withan optical axis of the lens.
 7. The lens of claim 1, wherein the lensfurther comprises a third light emitting surface formed between thesecond light emitting surface and the light source recess and extendingfrom the light source recess to the second light emitting surface. 8.The lens of claim 7, wherein the third light emitting surface has anintersecting line with the second light emitting surface and a tangentline of the intersecting line in peak is parallel to an intersectingline of the first, second light emitting surfaces.
 9. An LED modulehaving at least an LED, and at least a lens mounted in the light path ofone LED, the lens comprising: an optical axis; a light source recess fordisposing a light source; a first light emitting surface facing to thelight source recess; and a second light emitting surface intersectingwith the first light emitting surface and being on same side of thelight source recess with the first light emitting surface, anintersecting line formed between the first light emitting surface andthe second light emitting surface, and spaced with the optical axis, aprofile of section of the first, second light emitting surface, which istaken along the optical axis and perpendicular to the intersecting line,comprising at least one tangent line which has an acute angle with theoptical axis along the emitting orientation of the light emitted fromthe first, second light emitting surface.
 10. The LED module of claim 9,wherein the first light emitting surface has a plan view or comprises atleast a concave surface.
 11. The LED module of claim 9, wherein thesecond light emitting surface has a plan view or a cambered view. 12.The LED module of claim 9, wherein the first light emitting surface andthe second light emitting surface have a plurality of convex lensesdisposed thereon, each of the convex lenses have a radius, a height anda lateral dimensional which are designed according to beam wide ofincident light.
 13. The LED module of claim 9, wherein the lens furthercomprises a critical reflecting surface formed between the first, secondlight emitting surface and the light source recess, a transitionalsurface is formed between the critical reflecting surface and the first,second light emitting surface.
 14. The LED module of claim 9, whereinthe lens further comprises a third light emitting surface formed betweenthe second light emitting surface and the light source recess andextending from the light source recess to the second light emittingsurface.
 15. The LED module of claim 14, wherein the third lightemitting surface has an intersecting line with the second light emittingsurface and a tangent line of the intersecting line in peak is parallelto an intersecting line of the first, second light emitting surfaces.16. A illumination system comprising: an illuminated area; and at leastone LED module, the LED module comprising: at least an LED; and at leasta lens mounted in the light path of one LED, the lens comprising: anoptical axis; a light source recess for disposing a light source; afirst light emitting surface facing to the light source recess; and asecond light emitting surface intersecting with the first light emittingsurface and being on same side of the light source recess with the firstlight emitting surface, an intersecting line formed between the firstlight emitting surface and the second light emitting surface, and spacedwith the optical axis, a profile of section of the first, second lightemitting surface, which is taken along the optical axis andperpendicular to the intersecting line, comprising at least one tangentline which has an acute angle with the optical axis along the emittingorientation of the light emitted from the first, second light emittingsurface.
 17. The illumination system of claim 16, wherein light emittedfrom the first light emitting surface illuminating the illuminated areawhich is farther to the LED module, while light emitted from the secondlight emitting surface illuminating the illuminated area which is closerto the LED module.
 18. The illumination system of claim 17, wherein theoptical axis passes through the first light emitting surface.
 19. Theillumination system of claim 16, wherein the lens further comprises athird light emitting surface formed between the light source recess andthe second light emitting surface and extending from the light sourcerecess to the second light emitting surface.
 20. The illumination systemof claim 19, wherein the third light emitting surface has anintersecting line with the second light emitting surface and a tangentline of the intersecting line in peak is parallel to an intersectingline of the first, second light emitting surfaces.